Among these methods, only a few can be carried out conveniently in the laboratory, and most suffer from drawbacks. Some of the drawbacks are the involvement of two distinct reaction steps, and the use of toxic, expensive, unstable, moisture-sensitive and corrosive reagents. Some of the methods require stringent reaction conditions such as sub-zero temperature (−50 °C), long reaction times and hazardous solvents, and give mixtures of products. Moreover, ...
